1. Field of the Invention
The invention relates to a rope guide system for an aerial ropeway, particularly a circuital aerial ropeway, comprising a haulage rope, configured to form two haulage rope loops which, in the region of the haulage path, are guided parallely side by side at the same height to form an ascending lane and a descending lane for moving vehicles coupled to the lanes.
2. Description of the Related Art
A conventional aerial ropeway system having improved stability against crosswinds or other unstable conditions includes a rope guide system having two haulage ropes. In the region of the haulage path, the two ropes are guided parallely, side by side at the same height to form ascending and descending lanes whose widths correspond approximately to that of the vehicles coupled to the ropes.
For example, a conventional rope guide system, known as a QMC system (Quad Mono Cable system), has four individual, endless haulage ropes, each of which forms a rope loop. Each rope loop is reversed at the valley station and at the mountain station by a respective reversing wheel. All of the reversing wheels have an axis of rotation mounted approximately horizontal. A traction strand, to which the vehicles are coupled on both sides for ascending and descending, are formed on each pair of ropes by respective synchronous rope regions. The return strand of each rope loop is secured in order to form equal tensile forces in the four haulage ropes.
The four reversing wheels of a station are driven in opposite directions in pairs by a reversing gear unit, such as that described in the U.S. periodical "Ski Area Management", May 1988, pp 102-103 and 129 The four reversing wheels may also be driven in the same direction and be synchronized by a control device to run in paired synchronism. The haulage ropes can be crossed by respective deflector wheels to form two pairs of rope loops running in opposite directions (see, EP 285 516 A2). For emergency operation, the diameters of the rope pulleys on the drive wheels can be mechanically equalized.
The system described in European Patent Application EP 93 680 B1 includes two individual, endless haulage ropes, each of which forms a rope loop. To form the inner and outer rope loops which rotate in the same direction, the reversing wheels at the valley and mountain stations may be laterally offset in relation to One another (see FIGS. 16 and 17 of EP 93 680 B1) or may be arranged coaxially (see FIG. 15 of EP 93 680 B1). The haulage ropes guided parallely side by side at the same height in the region of the haulage path are directed to form the ascending and descending lanes of the same lane width for the coupled vehicles. The two driven reversing wheels have drives independent of one another, and are synchronized to the same rope haulage speed.
European Patent Application EP 399 919 B1 describes a rope guide system having two individual haulage ropes, each of which is endless, to form the inner and outer rope loops. Two driven reversing wheels, offset laterally in relation to one another, are provided at the driving station. The reversing station includes two traction-driven reversing wheels, offset laterally in relation to one another. Four deflector wheels, at each of the two stations, direct the four haulage ropes, guided parallely side by side at the same height in the region of the haulage path, to and away from the reversing wheels in different height positions in planes which are at an angle to the coupling points.
In this known rope guide system, two rope loops each having two synchronous regions for the ascending and descending lanes respectively are formed by crossing the two haulage ropes at both the driving station and at the reversing station. Hence, the two deflector wheels of the inner rope loop at each of the two stations are inclined, in order to change the running grooves on the reversing wheels while forming the rope crossing point. The two driven reversing wheels have drives which are independent of each other and are synchronized to achieve the same rope haulage speed in the two rope loops.
The rope guide systems described above, which have two or four individual, endless haulage ropes forming the inner and outer rope loops, is fairly expensive. Each individual haulage rope must be secured separately to obtain equal tensile forces in the individual pairs of ropes of each rope loop. Also, the pairs of ropes of different rope loops must be monitored for identical tensile forces and, if necessary, adjusted accordingly (see, for example, FIGS. 16 and 17 of EP 93 680 B1). To synchronize the rope haulage speed in the two rope loops, it is necessary to have a control device to which the rope haulage speed measured in each rope loop is fed as input signals, whereupon said device equalizes the speed of rotation of the respective drive motor.
A rope guide system having the generic features initially mentioned above is described in DE 37 12 941 C2. The two rope loops are formed from a single endless haulage rope crossed once to form inner and outer rope loops running in the same direction. Both the mountain and valley stations include a pair of coaxially mounted reversing wheels, by which the haulage ropes in the region of the haulage path are guided parallel side by side at the same height. The two rope loops are deflected so as to be offset in height in planes at an angle to the coupling stations.
The haulage ropes of the inner rope loop can run directly into the running grooves in the reversing wheels. However, the rope regions of the outer rope loop must be deflected in a lateral direction out of their position in which they lie one above the other in the reversing region, so as to form two synchronous lanes between the inner and outer rope loops. To accomplish this, four additional deflector wheels are necessary, one in on each of the inlet and outlet sides on each reversing wheel.
In addition, according to DE 37 12 941 C2, the two driven reversing wheels are coupled directly for conjoint rotation, or are replaced by a single rope pulley having two running grooves thus requiring only one drive for the two rope loops. Since the operative diameters at the two running grooves of the driving wheel differ from one another because of manufacturing tolerances and the like, and also due to wear and tear, the operative diameters on the driving wheels are never exactly equal. Hence, the rope haulage speeds differ slightly from one another in the two rope loops. Because of this, increased friction and thus increased wear occur on the driving wheel and may lead to the formation of frictional oscillations which are accompanied by undesirable noise and are transmitted through the haulage rope to the vehicles.